A plasma is a thermally highly heated electrically conductive gas that is composed of positive and negative ions, electrons and excited and neutral atoms and molecules.
Various gases, e.g., monatomic argon and/or the diatomic gases hydrogen, nitrogen, oxygen or air are used as a plasma gas. These gases ionize and dissociate by the energy of the plasma arc.
The parameters of the plasma jet can be highly influenced by the design of the nozzle and of the electrode. These parameters of the plasma jet are e.g. the jet diameter, the temperature, the energy density and the flow speed of the gas.
In plasma cutting, the plasma is usually constricted by a nozzle which may be gas-cooled or water-cooled. Energy densities of up to 2×106 W/cm2 can thereby be achieved. Temperatures arise in the plasma jet of up to 30,000° C. which allow very high cutting speeds at all electrically conductive materials in combination with the high flow speed of the gas.